Thermoelectric power generation system

ABSTRACT

A thermoelectric power generation system including a plurality of thermoelectric power generation devices. Each of the thermoelectric power generation devices includes: a heating unit having a heat medium passage in which a heat medium flows; a cooling unit having a cooling liquid passage in which a cooling liquid flows; a thermoelectric element having the heating unit and the cooling unit so as to generate power by utilizing a temperature difference between a condensation temperature of the heat medium and a temperature of the cooling liquid; and a heat transfer pipe communicated with the heat medium passage to form a circulation path in which the heat medium circulates. The heat transfer pipes of the respective thermoelectric power generation devices are arranged in a single flow path in which a high temperature fluid flows. The heat medium passages of the thermoelectric power generation devices are structured to communicate with each other.

CROSS REFERENCES TO RELATED APPLICATIONS

This application is a national stage application pursuant to 35 U.S.C. §371 of International Application No. PCT/JP2017/034918, filed on Sep.27, 2017, which claims priority under 35 U.S.C. § 119 to Japanese PatentApplication No. 2016-208955, filed on Oct. 25, 2016, the disclosures ofwhich are hereby incorporated by reference in their entireties

TECHNICAL FIELD

The present invention relates to a thermoelectric power generationsystem including a plurality of thermoelectric power generation devicesconfigured to generate power by utilizing a temperature difference.

BACKGROUND ART

An example of such a type of traditional thermoelectric power generationsystem is disclosed in Patent Literature 1 (hereinafter referred to asPTL 1). PTL 1 discloses a thermoelectric power generation system havinga plurality of thermoelectric power generation devices arranged around aheat source, the system being configured to vary the distance betweenthe heat source and each of the thermoelectric power generation devicesaccording to changes over time in the temperature of the heat source.

CITATION LIST Patent Literature

PTL 1: Japanese Patent Application Laid-Open No. 2011-176131

SUMMARY OF INVENTION Technical Problem

However, the thermoelectric power generation system of PTL 1 stillleaves a room for improvement in terms of suppressing and reducingunevenness in the power generation amount among the thermoelectric powergeneration devices.

To solve the above problem, the present invention provides athermoelectric power generation system that can suppress or reduceunevenness in the power generation amount among the thermoelectric powergeneration devices.

Solution to Problem

A thermoelectric power generation system related to an aspect of thepresent invention is a thermoelectric power generation system includinga plurality of thermoelectric power generation devices, wherein

each of the thermoelectric power generation devices includes

a heating unit having a heat medium passage in which a heat mediumflows,

a cooling unit having a cooling liquid passage in which a cooling liquidflows,

a thermoelectric element having the heating unit on one side and thecooling unit on the other side, the thermoelectric element configured togenerate power by utilizing a temperature difference between acondensation temperature of the heat medium that undergoes latent heattransfer in the heat medium passage and a temperature of the coolingliquid, and

a heat transfer pipe communicated with the heat medium passage to form acirculation path in which the heat medium is circulated,

the heat transfer pipes of the respective thermoelectric powergeneration devices being arranged in a single flow path in which a hightemperature fluid flows, and

the heat medium passages of the thermoelectric power generation devicesbeing structured to communicate with each other.

A thermoelectric power generation system related to another aspect ofthe present invention is a thermoelectric power generation systemincluding a plurality of thermoelectric power generation devices,wherein

each of the thermoelectric power generation devices includes

a heating unit having a heat medium passage in which a heat mediumflows,

a cooling unit having a cooling liquid passage in which a cooling liquidflows,

a thermoelectric element having the heating unit on one side and thecooling unit on another side, the thermoelectric element configured togenerate power by utilizing a temperature difference between acondensation temperature of the heat medium that undergoes latent heattransfer in the heat medium passage and a temperature of the coolingliquid, and

a heat transfer pipe communicated with the heat medium passage to form acirculation path in which the heat medium is circulated,

the heat transfer pipes of the respective thermoelectric powergeneration devices being arranged in a single flow path in which a hightemperature fluid flows,

the circulation passages of the respective thermoelectric powergeneration devices having equal volumes, and

an amount of heat medium filling the circulation path of any of thethermoelectric power generation devices whose heat transfer pipe is in aposition where a higher quantity of heat is received from the hightemperature fluid being smaller than an amount of heat medium fillingthe circulation path of any of the thermoelectric power generationdevices whose heat transfer pipe is in a position where a lower quantityof heat is received from the high temperature fluid.

Advantageous Effects of Invention

As described above, the thermoelectric power generation system of thepresent invention can suppress or reduce unevenness in the powergeneration amount among the thermoelectric power generation devices.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1A A diagram showing a schematic structure of a thermoelectricpower generation device included in a thermoelectric power generationsystem related to Embodiment 1 of the present invention.

FIG. 1B A diagram showing a schematic structure of a thermoelectricpower generation device included in a thermoelectric power generationsystem related to Embodiment 1 of the present invention, as viewed fromthe back.

FIG. 2 A diagram showing a schematic structure of a heating unit of athermoelectric power generation device included in a thermoelectricpower generation system related to Embodiment 1 of the presentinvention.

FIG. 3 A diagram showing a schematic structure of a cooling unit of athermoelectric power generation device included in a thermoelectricpower generation system related to Embodiment 1 of the presentinvention.

FIG. 4 A diagram showing a schematic structure of the thermoelectricpower generation system related to Embodiment 1 of the present inventionas viewed in a height direction.

FIG. 5 A schematic diagram of the thermoelectric power generation systemusing the thermoelectric power generation device related to Embodiment 1of the present invention.

FIG. 6 A schematic diagram of a heat medium system of the thermoelectricpower generation system related to Embodiment 1 of the presentinvention.

FIG. 7 A diagram showing a schematic structure of a thermoelectric powergeneration device related to Embodiment 2 of the present invention, asviewed in a height direction.

FIG. 8 A diagram showing a schematic structure of a modification of athermoelectric power generation device connecting a heat transfer pipeand a heat medium passage through an attaching part.

FIG. 9 A diagram showing a schematic structure of a modification of athermoelectric power generation device connecting a heat transfer pipeand a heat medium passage through an attaching part, as viewed in aheight direction.

FIG. 10 A diagram showing a schematic structure of a modification of athermoelectric power generation device connecting a heat transfer pipeand a heat medium passage through a detachable communication pipe.

FIG. 11 A diagram showing a schematic structure of a modification of athermoelectric power generation device connecting a heat transfer pipeand a heat medium passage through a detachable communication pipe.

FIG. 12 A diagram showing a schematic structure of a modification of athermoelectric power generation device with an attaching part having abent portion bent in such a manner that the heating unit, the coolingunit, and the thermoelectric element extend along a wall surface of aflow path.

DESCRIPTION OF EMBODIMENTS

(Findings on which the Present Invention is Based)

The inventors of the present invention have obtained the followingfindings, as a result of intensive research for suppressing or reducingunevenness in the power generation amount among the thermoelectric powergeneration devices.

A thermoelectric power generation device has a heating unit having aheat medium passage on one surface of a thermoelectric element and acooling unit including a coolant passage on another surface of thethermoelectric element, and configured to generate power by utilizing atemperature difference between the heat medium flowing in the heatmedium passage and the coolant flowing in the coolant passage. Thethermoelectric power generation system of PTL 1 includes a plurality ofthermoelectric power generation devices arranged around a heat source,so that the heat source serves as a heating unit shared among thethermoelectric power generation devices. Further, a space between theheat source and each of the thermoelectric power generation devicesserve as a heat medium passage, and the air in this space serves as theheat medium.

In the thermoelectric power generation system of PTL 1, each of thethermoelectric power generation devices is brought closer to or fartherfrom the heat source so that the thermoelectric elements ofthermoelectric power generation devices receive an even quantity of heatfrom the heat source. Such a structure however requires that the heatfrom the heat source be evenly radiated to the thermoelectric elementsof the thermoelectric power generation devices. However, due toenvironmental conditions and the like, the heat from the heat source maynot be evenly radiated to the surroundings. In such a case, the quantityof heat received may be different among the thermoelectric powergeneration devices, which leads to unevenness in the difference in thepower generation amount among the thermoelectric power generationdevices.

The thermoelectric power generation system of PTL 1 adopts the air asthe heat medium, and since the air flowing in the heat medium passagestays in the same phase, the air undergoes sensible heat transfer. Inother words, the temperature of the heat medium changes while it flowsin the heat medium passage.

Meanwhile, the inventors of the present invention have found that, bycausing a phase transition of the heat medium (e.g. from gas to liquid)while the heat medium flows in the heat medium passage, the temperatureof the heat medium can be constant and unevenness in the powergeneration amount among the thermoelectric power generation devices canbe suppressed or reduced. That is, during latent heat transfer of theheat medium, the condensation temperature of the heat medium isconstant. By utilizing this, the temperature of the heat medium in thethermoelectric power generation devices can be made constant even whenthe quantity of heat received from the heat source varies among thethermoelectric power generation devices. As a result, unevenness in thepower generation amount among the thermoelectric power generationdevices can be suppressed or reduced.

Further, the inventors of the present invention have found thatunevenness in the quantity of heat received by the thermoelectric powergeneration devices can be suppressed or reduced and unevenness in thepower generation amount among the thermoelectric power generationdevices can be suppressed or reduced, by providing each of thethermoelectric power generation devices with a heat transfer pipecommunicating to the heat medium passage, and arranging the respectiveheat transfer pipes in a single flow path in which a high temperaturefluid flows.

Based on these findings, the inventors of the present invention havearrived at the following invention.

A thermoelectric power generation system related to an aspect of thepresent invention is a thermoelectric power generation system includinga plurality of thermoelectric power generation devices, wherein

each of the thermoelectric power generation devices includes

a heating unit having a heat medium passage in which a heat mediumflows,

a cooling unit having a cooling liquid passage in which a cooling liquidflows,

a thermoelectric element having the heating unit on one side and thecooling unit on another side, the thermoelectric element configured togenerate power by utilizing a temperature difference between acondensation temperature of the heat medium that undergoes latent heattransfer in the heat medium passage and a temperature of the coolingliquid, and

a heat transfer pipe communicated with the heat medium passage to form acirculation path in which the heat medium is circulated,

the heat transfer pipes of the respective thermoelectric powergeneration devices being arranged in a single flow path in which a hightemperature fluid flows,

the heat medium passages of the thermoelectric power generation devicesbeing structured to communicate with each other.

In this structure, each of the thermoelectric power generation devicesgenerates power by utilizing the condensation temperature of the heatmedium that undergoes latent heat transfer in the heat medium passage.Therefore, unevenness in the power generation amount among thethermoelectric power generation devices can be suppressed or reduced.Further, unevenness in the quantity of heat received by thethermoelectric power generation devices can be suppressed or reduced andunevenness in the power generation amount among the thermoelectric powergeneration devices can be suppressed or reduced by providing each of thethermoelectric power generation devices with a heat transfer pipecommunicating to the heat medium passage, and arranging the respectiveheat transfer pipes in a single passage in which a high temperaturefluid flows. Further, since the heat medium passages of thethermoelectric power generation devices are in communication with oneanother, unevenness in the power generation amount among thethermoelectric power generation devices can be further suppressed orreduced.

It should be noted that the heat medium passages of the thermoelectricpower generation devices may be communicated with one another through apressure equalizer so that the pressure inside the heat medium passageis equalized.

With this structure, unevenness in the power generation amount among thethermoelectric power generation devices can be further suppressed orreduced by equalizing the pressure in the heat medium passage of thethermoelectric power generation devices.

It should be noted that the pressure equalizer is a member thatequalizes the pressure inside the heat medium passages of thethermoelectric power generation devices, and does not necessarily haveto be a member in which the heat medium flows. Therefore, a maximumcross section of the pressure equalizer perpendicularly crossing thedirection in which the pressure equalizer extends may be smaller than aminimum cross section of the heat medium passage perpendicularlycrossing the direction in which the heat medium passage extends.

A thermoelectric power generation system related to another aspect ofthe present invention is a thermoelectric power generation systemincluding a plurality of thermoelectric power generation devices,wherein

each of the thermoelectric power generation devices includes

a heating unit having a heat medium passage in which a heat mediumflows,

a cooling unit having a cooling liquid passage in which a cooling liquidflows,

a thermoelectric element having the heating unit on one side and thecooling unit on another side, the thermoelectric element configured togenerate power by utilizing a temperature difference between acondensation temperature of the heat medium that undergoes latent heattransfer in the heat medium passage and a temperature of the coolingliquid, and

a heat transfer pipe communicated with the heat medium passage to form acirculation path in which the heat medium is circulated,

the heat transfer pipes of the respective thermoelectric powergeneration devices being arranged in a single flow path in which a hightemperature fluid flows,

the circulation passages of the respective thermoelectric powergeneration devices having equal volumes,

an amount of heat medium filling the circulation path of any of thethermoelectric power generation devices whose heat transfer pipe is in aposition where a higher quantity of heat is received from the hightemperature fluid being smaller than an amount of heat medium fillingthe circulation path of any of the thermoelectric power generationdevices whose heat transfer pipe is in a position where a lower quantityof heat is received from the high temperature fluid.

In this structure, each of the thermoelectric power generation devicesgenerates power by utilizing the condensation temperature of the heatmedium that undergoes latent heat transfer in the heat medium passage.Therefore, unevenness in the power generation amount among thethermoelectric power generation devices can be suppressed or reduced.Further, unevenness in the quantity of heat received by thethermoelectric power generation devices can be suppressed or reduced andunevenness in the power generation amount among the thermoelectric powergeneration devices can be suppressed or reduced by providing each of thethermoelectric power generation devices with a heat transfer pipecommunicating to the heat medium passage, and arranging the respectiveheat transfer pipes in a single passage in which a high temperaturefluid flows. Further, since an amount of heat medium filling eachthermoelectric power generation device is varied according to thequantity of heat received from the high temperature fluid, the pressureinside the heat medium passages of the thermoelectric power generationdevices can be equalized, and unevenness in the power generation amountamong the thermoelectric power generation devices can be furthersuppressed and reduced.

The heat transfer pipe and the heat medium passage may be connectedthrough an attaching part, and

the attaching part may have a bent portion bent in such a manner thatthe heating unit, the cooling unit, and the thermoelectric elementextend in a direction along the wall surface of a flow path.

With this structure, the space taken by the thermoelectric powergeneration system can be reduced.

A thermoelectric power generation device related to another aspect ofthe present invention includes:

a heating unit having a heat medium passage in which a heat mediumflows;

a cooling unit having a cooling liquid passage in which a cooling liquidflows;

a thermoelectric element having the heating unit on one side and thecooling unit on another side, the thermoelectric element configured togenerate power by utilizing a temperature difference between acondensation temperature of the heat medium that undergoes latent heattransfer in the heat medium passage and a temperature of the coolingliquid; and

a heat transfer pipe communicated with the heat medium passage to form acirculation path in which the heat medium is circulated, wherein

the heat transfer pipe is arranged in a flow path in which a hightemperature fluid flows, and

the heat transfer pipe and the heat medium passage are connected throughan attaching part.

This structure can improve the degree of freedom in connecting the heattransfer pipe and the heat medium passage.

It should be noted that the attaching part may have a flange partattached in such a manner as to close an opening portion provided on thewall surface of the flow path, the opening portion allowing the heattransfer pipe to pass therethrough.

With this structure, for example, the heat transfer pipe can be easilyarranged in the flow path by inserting the heat transfer pipe in anopening portion provided on the wall surface of the flow path, and theopening portion can be closed by the flange part. Thus, thethermoelectric power generation device can be easily attached to thewall surface of the flow path.

Further, the attaching part may have a detachable communication pipewhich communicates the heat transfer pipe and the heat medium passage.

In this structure with the detachable communication pipe, for example, acommunication pipe with a suitable length according to the thickness ofthe wall of the flow path, the thickness of the insulating materialformed on the wall surface of the flow path, or the like can be used.Therefore, the degree of freedom in the place of installing thethermoelectric power generation device can be improved.

Further, the attaching part may have a bent portion bent in such amanner that the heating unit, the cooling unit, and the thermoelectricelement extend in a direction along the wall surface of the flow path.

With this structure, the space of the thermoelectric power generationdevice can be saved.

The following describes embodiments with reference to attached drawings.In each of the drawings, elements are exaggerated for the sake of easierunderstanding.

Embodiment 1

A thermoelectric power generation system related to Embodiment 1includes a plurality of thermoelectric power generation devices. First,the following describes the thermoelectric power generation devices.

[Thermoelectric Power Generation Device]

FIG. 1A shows a schematic structure of a thermoelectric power generationdevice 1 related to Embodiment 1. The directions X, Y, and Z in FIG. 1Aindicate the longitudinal direction, lateral direction, and the heightdirection of the thermoelectric power generation device 1, respectively.The longitudinal direction, the lateral direction, and the heightdirection mean the length direction, short direction, and the up-downdirection of the thermoelectric power generation device 1, respectively.FIG. 1B is a diagram showing a schematic structure of the thermoelectricpower generation device 1 as viewed from behind (in X direction).

As shown in FIG. 1A and FIG. 1B, the thermoelectric power generationdevice 1 includes a thermoelectric element 2 in which a heating unit 3is provided on one surface and a cooling unit 4 is provided on the othersurface. In Embodiment 1, the thermoelectric elements 2 are provided onboth sides of the heating unit 3, and the cooling units 4 are providedon both sides of the heating unit 3 so as to face each other across thethermoelectric elements 2. In Embodiment 1, the heating unit 3 isconnected to a heat transfer pipe 6 arranged in a flow path 5 in which ahigh temperature fluid flows.

<Thermoelectric Element>

The thermoelectric element 2 is an element having two surfaces, i.e.,one surface on which the heating unit 3 is provided (thehigh-temperature side) and the other surface on which the cooling unit 4is provided (on the low-temperature side). In the thermoelectric element2, the heating unit 3 heats the one surface and the cooling unit 4 coolsthe other surface, thereby generating power using the temperaturedifference. The thickness of the thermoelectric element 2 is designed tobe smaller than the size (width) of the first side and the second sideof the thermoelectric element 2. Specifically, the thermoelectricelement 2 is formed in a plate shape. In Embodiment 1, thermoelectricmodules 20 a and 20 b each having a plurality of serially connectedthermoelectric elements 2 are attached to both sides of the heating unit3. Specifically, on both sides of the heating unit 3, the thermoelectricmodules 20 a, 20 b each having 20 thermoelectric elements 2 of fourcolumns×five rows are attached. The number of thermoelectric elements 2is not limited to this. For example, the thermoelectric power generationdevice 1 may have one thermoelectric element 2 attached to each of bothsides of the heating unit 3.

<Heating Unit>

The heating unit 3 is made of a metal material with excellent thermalconductivity. The heating unit 3 is formed in a plate shape, whichcontacts first sides of the thermoelectric elements 2. The heating unit3 is connected to the heat transfer pipe 6. The heating unit 3 and theheat transfer pipe 6 have internal spaces 7 a, 7 b communicating witheach other. In the internal space 7 a of the heating unit 3 and theinternal space 7 b of the heat transfer pipe 6, a heat medium isenclosed. Further, the internal space 7 a of the heating unit 3 and theinternal space 7 b of the heat transfer pipe 6 form a circulation path 7in which the heat medium is circulated. That is, the heat transfer pipe6 communicates with the heat medium passage to form a circulation path 7in which heat medium is circulated.

The heat transfer pipe 6 is arranged in the flow path 5 and vaporizesthe heat medium flowing in the internal space 7 b which is a part of thecirculation path 7, by using the heat of the high temperature fluidflowing in the flow path 5. That is, the heat transfer pipe 6 functionsas a vaporizing unit for vaporizing the heat medium. The heating unit 3condenses the heat medium vaporized in the internal space 7 b of theheat transfer pipe 6. That is, the heating unit 3 functions as acondensing unit for condensing the heat medium. In Embodiment 1, wateris used as the heat medium. Further, the flow path 5 is, for example, anengine duct of an exhaust gas through which a high-temperature exhaustgas flows. In the flow path 5, the high temperature fluid flows in adirection towards the paper surface of FIG. 1A, i.e., in the Ydirection.

FIG. 2 shows a schematic structure of the heating unit 3 and the heattransfer pipe 6 of the thermoelectric power generation device 1. Asshown in FIG. 2, the heat transfer pipe 6 is structured so as to have alarge contact area with the high temperature fluid flowing in the flowpath 5, when viewed in the direction in which the high temperature fluidflows, i.e., the Y direction. Specifically, the heat transfer pipe 6 hasa plurality of tubular members 61 extending in the X direction and aplurality of bent portions 62 connecting the tubular members 61 to eachother, as viewed from the Y direction. The plurality of tubular members61 are arranged with a predetermined interval in the Z direction andtheir end portions are connected through the bent portions 62, whenviewed in the Y direction. With the plurality of tubular members 61connected through the bent portions 62 as described, the heat transferpipe 6 forms a continuous pipe having a plurality of bent portions.

In the internal space 7 a of the heating unit 3, a heat medium passagein which the heat medium flows is formed. In Embodiment 1, the heatmedium passage is formed so that the heat medium spreads throughout theentire heating surface of the thermoelectric element 2. Specifically, asshown in FIG. 2, a plurality of heat medium passages extending in the Zdirection are formed in the internal space 7 a of the heating unit 3.The heat medium passages in the internal space 7 a of the heating unit 3may be, for example, inclined towards the X direction, as long as theheat medium flows in the direction of gravity.

<Circulation Path>

The circulation path 7 is formed through the internal space 7 a of theheating unit 3 and the internal space 7 b of the heat transfer pipe 6.The heat medium circulates in the internal space 7 a of the heating unit3 and the internal space 7 b of the heat transfer pipe 6. Specifically,when the heat transfer pipe 6 is heated by the high temperature fluidflowing in the flow path 5, the liquid heat medium flowing in the heattransfer pipe 6 is turned into vapor. In other words, the heat medium isvaporized in the internal space 7 b of the heat transfer pipe 6 and thephase of the heat medium changes from liquid to gas. The vapor isdischarged from an opening end portion 63 in a high position of the heattransfer pipe 6 to the heat medium passage in the internal space 7 a ofthe heating unit 3. The vapor discharged into the heat medium passage inthe internal space 7 a of the heating unit 3 falls in the direction ofgravity while being poured onto the heating surface of the heating unit3, and is condensed by radiating heat from the heating surface to heatthe thermoelectric elements 2. In other words, the phase of the heatmedium changes from gas to liquid in the internal space 7 a of theheating unit 3. That is, the heat medium undergoes latent heat transfer,and the condensation temperature of the heat medium is constant. Theheat medium condensed flows from an open end portion 64 in a lowposition of the heat transfer pipe 6 into the heat medium passage in theinternal space 7 b of the heat transfer pipe 6. The heat medium havingflowed into the internal space 7 b of the heat transfer pipe 6 is againheated by the high temperature fluid flowing into the flow path 5, andthe phase of the heat medium is changed from liquid to gas. Asdescribed, the heat medium spontaneously circulates in the circulationpath 7 formed by the internal space 7 a of the heating unit 3 and theinternal space 7 b of the heat transfer pipe 6. In other words, by usingthe phase change of the heat medium, the heat medium is repeatedlycirculated in the circulation path 7 formed by the internal space 7 a ofthe heating unit 3 and the internal space 7 b of the heat transfer pipe6, without power of a pump and the like.

<Cooling Unit>

The cooling units 4 are each made of a metal material with excellentthermal conductivity. The cooling units 4 are formed in a plate shape,which contact the second sides of the thermoelectric elements 2.Further, inside each of the cooling units 4, a cooling liquid passage inwhich a cooling liquid flows is formed.

FIG. 3 shows a schematic structure of the cooling unit 4 of thethermoelectric power generation device 1. As shown in FIG. 3, inside thecooling unit 4, a plate-shape cooling liquid passage 40 is formed insuch a manner that the cooling liquid is spread throughout the entirecooling surface of the cooling unit 4 which contacts the thermoelectricelement 2. Specifically, the cooling liquid passage 40 has a pluralityof passages extending in the X direction, which are connected with oneanother. The cooling liquid passage 40 is provided with a cooling liquidinflow pipe 41 on its low side, and a cooling liquid discharge pipe 42on its high side. The cooling liquid having flowed from the coolingliquid inflow pipe 41 into the cooling liquid passage 40 cools thecooling surface in contact with the second side of the thermoelectricelement 2, and then discharged from the cooling liquid discharge pipe42. Although the cooling liquid passage 40 in Embodiment 1 is formed ina plate shape such that the cooling liquid spreads throughout the entirecooling surface in contact with the thermoelectric element 2, the shapeof the cooling liquid passage 40 is not limited as long as the secondside of the thermoelectric element 2 is entirely and evenly cooled.Further, the plurality of passages of the cooling liquid passage 40inside the cooling unit 4 may extend not only in the X direction butalso in the Z direction. In Embodiment 1, water is used as the coolingliquid.

[Thermoelectric Power Generation System]

A thermoelectric power generation system related to Embodiment 1 isdescribed.

FIG. 4 is a diagram showing a schematic structure of the thermoelectricpower generation system 10A related to Embodiment 1 as viewed in aheight direction. As shown in FIG. 4, the thermoelectric powergeneration system 10A includes four thermoelectric power generationdevices 1. Heat transfer pipes 6 of the thermoelectric power generationdevice 1 are arranged in a single flow path 5 in which a hightemperature fluid flows. The heat medium passages of the thermoelectricpower generation devices 1 are communicated with one another.Specifically, the heat medium passages of the thermoelectric powergeneration devices 1 are communicated with one another by a pressureequalizer 8 in such a manner that the pressures in the heat mediumpassages are equalized.

<Electric System>

FIG. 5 is a schematic diagram of an electric system of a thermoelectricpower generation system 10A. As shown in FIG. 5, the thermoelectricpower generation system 10A includes: four thermoelectric powergeneration devices 1, an inverter 11, and an electric load 12. In thethermoelectric power generation system 10A, the four thermoelectricpower generation devices 1 are connected in parallel. The fourthermoelectric power generation devices 1 connected in parallel areconnected to the inverter 11. The inverter 11 is connected to theelectric load 12. In the thermoelectric power generation system 10A,power generated by the four thermoelectric power generation devices 1 issupplied to the electric load 12 through the inverter 11.

<Heat Medium System>

FIG. 6 is a schematic diagram of a heat medium system of athermoelectric power generation system 10A. In FIG. 6, the dotted lineand the one dot chain line indicate the line of the heat medium, and thesolid line indicates the line of the cooling liquid. First, a flow ofthe heat medium is described. As shown in FIG. 6, the heat medium linesL 1, L 2, and L 3 are connected to the heating unit 3 of thethermoelectric power generation device 1. To the heat medium lines L1,L2, and L3, valves are provided respectively. While the heat mediumspontaneously circulates inside the heating unit 3, the heat mediumlines L1, L2, L3 are closed. The valve provided to the heat medium lineL3 is a pressure valve.

The heat medium line L1 is a line for loading water to become the heatmedium. To supply the heat medium inside the heating unit 3, the valveof the heat medium line L1 is opened to supply the heat medium from atank 13 into the heating unit 3, through the heat medium line L1.

The heat medium line L2 is a line for evacuation using a vacuum pump 14.Evacuation is performed by using the vacuum pump 14 through the heatmedium line L2, while the heating unit 3 has no heat medium. After theevacuation, the heat medium in the tank 13 is supplied inside theheating unit 3 through the heat medium line L1.

The heat medium line L3 is a line for discharging the heat medium insidethe heating unit 3 to the tank 13. When the vapor pressure inside theheating unit 3 becomes higher than the tolerance of the pressure valveof the heat medium line L3, the pressure valve opens and the vaporinside the heating unit 3 is discharged to the heat medium line L3. Theheat medium discharged from the heating unit 3 flows in the heat mediumline L3, and is discharged to the tank 13 through a heat exchanger 15.Since water is used as the heat medium and as the cooling liquid inEmbodiment 1, the cooling liquid and the heat medium can be stored inthe tank 13.

Next, a flow of the cooling liquid is described. As shown in FIG. 6, thecooling liquid flows from the tank 13 to the cooling unit 4 through acooling liquid line L4, with the use of a pump and the like. The coolingliquid having flowed into the cooling unit 4 flows to a coolinginstallation 16 through a cooling liquid line L5. The coolinginstallation 16 is, for example, a cooling tower for cooling the coolingliquid. The cooling liquid cooled in the cooling installation 16 isstored in the tank 13.

[Effects]

The thermoelectric power generation system 10A related to Embodiment 1brings about the following effects.

In the thermoelectric power generation system 10A, each of thethermoelectric power generation devices 1 generates power by utilizingthe condensation temperature of the heat medium that undergoes latentheat transfer in the heat medium passage. Therefore, unevenness in thepower generation amount among the thermoelectric power generationdevices 1 can be suppressed or reduced. Further, unevenness in thequantity of heat received by the thermoelectric power generation devices1 can be suppressed or reduced and unevenness in the power generationamount among the thermoelectric power generation devices 1 can besuppressed or reduced by providing each of the thermoelectric powergeneration devices 1 with a heat transfer pipe 6 communicating to theheat medium passage, and arranging the respective heat transfer pipes 6in a single flow path 5 in which a high temperature fluid flows.

In Embodiment 1, the high temperature fluid flows within the flow path 5in the direction indicated by the broken line arrow. In this case, theheat of the high temperature fluid is taken away by the heat transferpipes 6 and the like as it flows from the upstream to the downstream ofthe flow direction, and the temperature of the high temperature fluidtherefore is decreased. Therefore, the quantity of heat received by theheat transfer pipe 6 arranged in the downstream of the flow direction ofthe high temperature fluid is smaller than the quantity of heat receivedby the heat transfer pipe 6 arranged upstream of the flow direction ofthe high temperature fluid.

In the thermoelectric power generation system 10A on the other hand,since the heat medium passages of the thermoelectric power generationdevices 1 are in communication with one another, unevenness in the powergeneration amount among the thermoelectric power generation devices 1can be further suppressed or reduced. Further, in the thermoelectricpower generation system 10A, the heat medium passages of thethermoelectric power generation devices 1 are communicated with oneanother by a pressure equalizer 8 in such a manner that the pressures inthe heat medium passages are equalized. With this structure, unevennessin the power generation amount among the thermoelectric power generationdevices 1 can be further suppressed or reduced by equalizing thepressure in the heat medium passage of the thermoelectric powergeneration devices 1.

Further, in the thermoelectric power generation system 10A, each of thethermoelectric power generation devices 1 can be made identical, andtherefore the mass productivity can be improved by modularizing thedevice.

It should be noted that the pressure equalizer 8 is a member thatequalizes the pressures inside the heat medium passages of thethermoelectric power generation devices 1, and is not a path forcirculating the heat medium. Therefore, a maximum cross section of thepressure equalizer 8 perpendicularly crossing the direction in which thepressure equalizer 8 extends may be smaller than a minimum cross sectionof the heat medium passage perpendicularly crossing the direction inwhich the heat medium passage extends. Further, a position of connectingthe pressure equalizer 8 to each of the thermoelectric power generationdevices 1 is not particularly limited; however, the position ispreferably where the heat medium having turned into liquid aftercondensed in the heat medium passage does not flow in.

It should be noted that Embodiment 1 deals with a thermoelectric powergeneration system 10A having four thermoelectric power generationdevices 1A; however, the present invention is not limited to this, aslong as the thermoelectric power generation system 10A includes at leastone thermoelectric power generation device 1.

Although Embodiment 1 adopts water as the heat medium and the coolingliquid, the present invention is not limited to this. The heat mediumand the cooling liquid may be different. Any heat medium may be adoptedprovided that the heat medium can change its phase between gas andliquid in the circulation path 7. Any given liquid may be adopted as acooling liquid, provided that cooling is possible.

Although Embodiment 1 deals with a case where the thermoelectric element2 is provided to one side of the heating unit 3, the present inventionis not limited to this. For example, the thermoelectric element 2 may beprovided on a surface of only one side of the heating unit 3.

Embodiment 2

[Overall Structure]

A thermoelectric power generation system related to Embodiment 2 of thepresent invention is described. It should be noted that Embodiment 2mainly describes differences from Embodiment 1. In Embodiment 2, thesame symbols are given to structures identical or similar to those ofEmbodiment 1. Further, the description of Embodiment 2 omitsdescriptions which overlaps with that of Embodiment 1.

FIG. 7 shows a schematic structure of a thermoelectric power generationsystem 10B related to Embodiment 2.

Embodiment 2 is different from Embodiment 1 in that the thermoelectricpower generation system 10B includes three thermoelectric powergeneration devices 1 and that the system is configured to change theamount of heat medium filling each of the thermoelectric powergeneration devices 1 according to the quantity of heat received from thehigh temperature fluid.

Specifically, an amount of heat medium filling a thermoelectric powergeneration device 1 whose heat transfer pipe 6 is arranged in a positionwhere a higher quantity of heat is received from the high temperaturefluid is smaller than an amount of heat medium filling a thermoelectricpower generation device 1 whose heat transfer pipe 6 is arranged in aposition where a lower quantity of heat is received from the hightemperature fluid. Therefore, the amount of heat medium filling thecirculation passage 7 (see FIG. 2) is the smallest in the thermoelectricpower generation device 1 whose heat transfer pipe 6 is in the upstreamposition of the flow direction of the high temperature fluid. Further,the amount of heat medium filling the circulation passage 7 (see FIG. 2)is the largest in the thermoelectric power generation device 1 whoseheat transfer pipe 6 is in the downstream position of the flow directionof the high temperature fluid. It should be noted that the circulationpassages of the respective thermoelectric power generation devices 1have equal volumes. For example, in order from the thermoelectric powergeneration device 1 positioned upstream of the flow direction of thehigh temperature fluid, the amount of heat medium filling each of thethermoelectric power generation devices 1 are 10%, 15%, and 20% of thetotal fillable amount, respectively.

[Effects]

The thermoelectric power generation system 10B related to Embodiment 2brings about the following effects.

In the thermoelectric power generation system 10B, each of thethermoelectric power generation devices 1 generates power by utilizingthe condensation temperature of the heat medium that undergoes latentheat transfer in the heat medium passage. Therefore, unevenness in thepower generation amount among the thermoelectric power generationdevices can be suppressed or reduced. Further, unevenness in thequantity of heat received by the thermoelectric power generation devices1 can be suppressed or reduced and unevenness in the power generationamount among the thermoelectric power generation devices 1 can besuppressed or reduced by providing each of the thermoelectric powergeneration devices 1 with a heat transfer pipe 6 communicating to theheat medium passage, and arranging the respective heat transfer pipes 6in a single flow path 5 in which a high temperature fluid flows.Further, since an amount of heat medium filling each thermoelectricpower generation device 1 is varied according to the quantity of heatreceived from the high temperature fluid, the pressure inside the heatmedium passages of the thermoelectric power generation devices 1 can beequalized, and unevenness in the power generation amount among thethermoelectric power generation devices 1 can be further suppressed andreduced.

Further, in the thermoelectric power generation system 10B, each of thethermoelectric power generation devices 1 can be made identical, andtherefore the mass productivity can be improved by modularizing thedevice.

It should be noted that the present invention is not limited to theembodiment described above but may be embodied in many different forms.For example, although the above embodiments deal with a case where theheat transfer pipe 6 and the heat medium passage in the internal space 7a of the heating unit 3 are directly connected, the present invention isnot limited to this. For example, as shown in FIG. 8 and FIG. 9, theheat transfer pipe 6 and the heat medium passage may be connectedthrough an attaching part 9. With this structure, the degree of freedomin connecting the heat transfer pipe 6 and the heat medium passage canbe improved.

Further, as shown in FIG. 8 and FIG. 9, the attaching part 9 may have aflange part 91 attached in such a manner as to close an opening portion5 a provided on the wall surface of the flow path 5, the opening portionallowing the heat transfer pipe 6 to pass therethrough. With thisstructure, for example, the heat transfer pipe 6 can be easily arrangedin the flow path 5 by inserting the heat transfer pipe 6 in the openingportion 5 a provided on the wall surface of the flow path 5, and theopening portion 5 a can be closed by the flange part 91. Thus, thethermoelectric power generation device 1 can be easily attached to thewall surface of the flow path 5. The opening portion 5 a may be anygiven form as long as it allows the heat transfer pipe 6 to be insertedinto the flow path 5. For example, a slit and the like can be adopted.The wall surface of the flow path 5 is, for example, the wall surface ofa cylindrical exhaust gas duct forming the flow path 5.

Further, As shown in FIG. 10 and FIG. 11, the attaching part 9 may havea detachable communication pipe 92A, 92B which communicates the heattransfer pipe 6 and the heat medium passage. In this structure with thedetachable communication pipe 92A, 92B, for example, the communicationpipe 92A, 92B having a suitable length according to the thickness of thewall of the flow path 5, the thickness of the insulating material 101,102 formed on the wall surface of the flow path 5, or the like can beused. Therefore, the degree of freedom in the place of installing thethermoelectric power generation device can be improved.

Further, as shown in FIG. 12, the attaching part 9 may have a bentportion 93 bent in such a manner that the heating unit 3, the coolingunit 4, and the thermoelectric element 2 extend in a direction along thewall surface of the flow path 5. With this structure, the space taken bythe thermoelectric power generation device 1 can be reduced.

It should be noted that the effects of the embodiments described abovecan be brought about by suitably combining any of the variousembodiments described above.

Although each of the above embodiments describes the present inventionwith a certain level of details, the details of the structures disclosedin these embodiments are modifiable. Further, modification incombinations and arrangement of elements in each embodiment are possiblewithout departing from the scope and spirit of the present disclosure.

INDUSTRIAL APPLICABILITY

Since unevenness in the power generation amount among the thermoelectricpower generation devices can be suppressed or reduced, the presentinvention is useful for a thermoelectric power generation system havinga plurality of thermoelectric power generation devices each configuredto generate power by utilizing heat of a high temperature fluid flowingin a passage such as an exhaust gas duct of an engine.

REFERENCE SIGNS LIST

-   -   1 thermoelectric power generation device    -   10A, 10B thermoelectric power generation system    -   11 inverter    -   12 electric load    -   13 tank    -   14 vacuum pump    -   15 heat exchanger    -   16 cooling installation    -   2 thermoelectric element    -   20 a, 20 b thermoelectric module    -   3 heating unit    -   4 cooling unit    -   40 cooling liquid passage    -   41 cooling liquid inflow pipe    -   42 cooling liquid discharge pipe    -   5 flow path    -   5 a opening portion    -   6 heat transfer pipe    -   61 tubular member    -   62 bent portion    -   63, 64 open end portion    -   7 circulation path    -   7 a, 7 b internal space    -   8 pressure equalizer    -   9 attaching part    -   91    -   92A, 92B communication pipe    -   93 bent portion    -   101, 102 insulating material    -   L1, L2, L3 heat medium line    -   L4, L5 cooling liquid line

The invention claimed is:
 1. A thermoelectric power generation systemcomprising: a plurality of thermoelectric power generation devices,wherein: each of the thermoelectric power generation devices comprises:a heating unit having a heat medium passage configured for flow of aheat medium flows, medium, a cooling unit having a cooling liquidpassage in which configured for flow of a cooling liquid, athermoelectric element having the heating unit on one side thereof andthe cooling unit on another side thereof, the thermoelectric elementconfigured to generate power by utilizing a temperature differencebetween a condensation temperature of the heat medium that undergoeslatent heat transfer in the heat medium passage and a temperature of thecooling liquid, and a heat transfer pipe in fluid communication with theheat medium passage to form a circulation path associated with the heatmedium, and each heat transfer pipe of the plurality of thermoelectricpower generation devices is arranged in a single flow path configuredfor flow of a high temperature fluid, each heat medium passage of theplurality of thermoelectric power generation devices is in fluidcommunication each other heat medium passage of the plurality ofthermoelectric power generation devices, and each circulation path ofthe plurality of thermoelectric power generation devices is configuredto include an amount of heat medium based on a position of acorresponding heat transfer pipe, the amount of heat medium based on afirst position of the corresponding heat transfer pipe less than anamount of heat medium based on a second position of the correspondingheat transfer pipe, the corresponding heat transfer pipe configured toreceive more heat in the first position than the second position.
 2. Thethermoelectric power generation system according to claim 1, wherein theheat medium passages of the thermoelectric power generation devices areconfigured to be in fluid communication via a pressure equalizer so thatthe pressure inside the heat medium passage is equalized.
 3. Thethermoelectric power generation system according to claim 2, wherein amaximum cross section of the pressure equalizer perpendicularly crossinga direction in which the pressure equalizer extends is smaller than aminimum cross section of the heat medium passage perpendicularlycrossing a direction in which the heat medium passage extends.
 4. Athermoelectric power generation system comprising: a plurality ofthermoelectric power generation devices, wherein: each of thethermoelectric power generation devices comprises: a heating unit havinga heat medium passage configured for flow of a heat medium, a coolingunit having a cooling liquid passage configured for flow of a coolingliquid, a thermoelectric element having the heating unit on one side andthe cooling unit on another side, the thermoelectric element configuredto generate power by utilizing a temperature difference between acondensation temperature of the heat medium that undergoes latent heattransfer in the heat medium passage and a temperature of the coolingliquid, and a heat transfer pipe in fluid communication with the heatmedium passage to form a circulation path associated with the heatmedium, and each heat transfer pipe of the plurality of thermoelectricpower generation devices is arranged in a single flow path configured toreceive a high temperature fluid, each circulation path of the pluralityof thermoelectric power generation devices has an equal volume, and anamount of heat medium filling the circulation path of any of thethermoelectric power generation devices whose heat transfer pipe is in aposition where a higher quantity of heat is received from the hightemperature fluid is smaller than an amount of heat medium filling thecirculation path of any of the thermoelectric power generation deviceswhose heat transfer pipe is in a position where a lower quantity of heatis received from the high temperature fluid.
 5. The thermoelectric powergeneration system according to claim 1, wherein: the heat transfer pipeand the heat medium passage are connected via an attaching part; and theattaching part has a bent portion bent in such a manner that the heatingunit, the cooling unit, and the thermoelectric element extend in adirection along a wall surface of the flow path.
 6. A thermoelectricpower generation device of a plurality of thermoelectric powergeneration devices, the thermoelectric power generation devicecomprising: a heating unit having a heat medium passage configured forflow of a heat medium; a cooling unit having a cooling liquid passageconfigured for flow of a cooling liquid; a thermoelectric element havingthe heating unit on one side and the cooling unit on another side, thethermoelectric element configured to generate power based on atemperature difference between a condensation temperature of the heatmedium that undergoes latent heat transfer in the heat medium passageand a temperature of the cooling liquid; a heat transfer pipe in fluidcommunication with the heat medium passage to form a circulation pathassociated with circulation of the heat medium; and wherein: the heattransfer pipe is arranged in a flow path configured for flow of a hightemperature fluid, the heat transfer pipe and the heat medium passageare connected to each other through an attaching part, the circulationpath is configured to include an amount of heat medium based on aposition of the heat transfer pipe; and the amount of heat medium isbased on a first position of the heat transfer pipe relative to a secondheat transfer pipe of a second thermoelectric power generation device ofthe plurality of thermoelectric power generation devices, the secondheat transfer pipe in the flow path, and the amount of heat medium inthe heat transfer pipe less than a second amount of heat medium in thesecond heat transfer pipe based on the heat transfer pipe beingpositioned in the flow path such that the heat transfer pipe receivesmore heat than the second heat transfer pipe.
 7. The thermoelectricpower generation device according to claim 6, wherein the attaching parthas a flange part attached in such a manner as to close an openingportion provided on a wall surface of the flow path, the opening portionconfigured to allow the heat transfer pipe to pass therethrough.
 8. Thethermoelectric power generation device according to claim 6, wherein theattaching part has a detachable communication pipe, the heat transferpipe and the heat medium passage configured to communicate via thedetachable communication pipe.
 9. The thermoelectric power generationdevice according to claim 6, wherein the attaching part has a bentportion bent in such a manner that the heating unit, the cooling unit,and the thermoelectric element extend in a direction along a wallsurface of the flow path.